U.S. patent application number 11/563260 was filed with the patent office on 2007-05-31 for angio capable portable x-ray fluoroscopy unit with sliding c-arm and variable pivot point.
Invention is credited to John K. Grady.
Application Number | 20070121790 11/563260 |
Document ID | / |
Family ID | 38120673 |
Filed Date | 2007-05-31 |
United States Patent
Application |
20070121790 |
Kind Code |
A1 |
Grady; John K. |
May 31, 2007 |
ANGIO CAPABLE PORTABLE X-RAY FLUOROSCOPY UNIT WITH SLIDING C-ARM
AND VARIABLE PIVOT POINT
Abstract
An "Angio Capable Portable X-Ray Fluoroscopy Unit with Sliding
C-Arm and Variable Pivot Point" is disclosed. It is a new Portable
C-Arm x-ray system for fluoroscopy (e.g., angio fluoroscopy) that
permits head-to-foot, or cranio-caudal, angulation without
appreciable degradation or rotation of the recorded image in the
segment of possible views most desired to be used for cardiac
angiography, generally between a vertical beam and 60 degrees to
the patient's left side from vertical. Applicant's preferred
embodiment comprises an portable x-ray device of the type having a
C-arm which "slides" through a fixed C-slider housing or sleeve
mounted onto a portable base, wherein: the C-slider housing is
mounted onto the portable base through a rotatable tilt bearing,
and the rotation axis of the bearing and fixed sleeve can be
repositioned, within an arcuate slot in the base, from
approximately horizontal, when the x-ray beam is vertical, to
between approximately 60 degrees and 40 degrees below horizontal in
a vertical plane.
Inventors: |
Grady; John K.; (Harvard,
MA) |
Correspondence
Address: |
HOLLAND & BONZAGNI, P.C.
171 DWIGHT ROAD, SUITE 302
LONGMEADOW
MA
01106-1700
US
|
Family ID: |
38120673 |
Appl. No.: |
11/563260 |
Filed: |
November 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60739712 |
Nov 25, 2005 |
|
|
|
Current U.S.
Class: |
378/198 |
Current CPC
Class: |
A61B 6/4405 20130101;
A61B 6/503 20130101; A61B 6/504 20130101; A61B 6/4441 20130101 |
Class at
Publication: |
378/198 |
International
Class: |
H05G 1/02 20060101
H05G001/02 |
Claims
1. In an portable x-ray device of the type having an x-ray source,
an image receptor, and a C-arm support apparatus, wherein a C-arm
slides in a stationary arc in a single X-Y plane through a C-sleeve
mounted on a portable base, the improvement comprising: a rotatable
tilt bearing means for pivoting the arc, and C-sleeve, in a Z-plane
around a pivot axis; and a sliding pivot point means for
repositioning the tilt bearing means, and pivot axis, in the X-Y
plane along an arcuate path from approximately horizontal, when the
x-ray beam is vertical, to approximately 60 degrees below
horizontal in a vertical plane.
2. In a portable x-ray device of the type having an x-ray source,
an x-ray beam, an image receptor assembly, and a C-arm support
apparatus, wherein a C-arm slides in an arc within a single plane
through a fixed C-slider housing, and the C-arm and C-slider
housing are mounted onto a base, the improvement comprising: a
rotatable tilt bearing means for pivoting the C-slider housing in a
rotational axis; the C-arm and C-slider housing are mounted onto
the base by the rotatable tilt bearing means; and, a sliding pivot
point means for selectively repositioning the rotational axis, plus
C-slider housing, along an arc from approximately horizontal, when
the x-ray beam is vertical, to between approximately 60 degrees and
40 degrees below horizontal in a vertical plane.
3. The device of claim 2 wherein the rotatable tilt bearing means
includes a rotatable tilt bearing and the C-arm and C-slider
housing are mounted onto the base by the rotatable tilt
bearing.
4. The device of claim 3 wherein the tilt bearing means comprises a
reversible drive motor, removably attached to the rotatable tilt
bearing, to selectively rotate the C-slider housing about the
C-slider pivot axis.
5. The device of claim 4 wherein the sliding pivot point means
comprises: an arcuate pivot carriage guide track mounted to the
base; a carriage with guide rollers which slides within the track,
wherein the carriage is attached to the C-slider housing by a
rotatable tilt bearing that rides atop a slot in the guide
track.
6. The device of claim 5 wherein a drive gearmotor selectively
locates the carriage and C-slider housing by a drive chain attached
to the carriage.
7. In a portable x-ray device of the type having an x-ray source,
an x-ray beam, an image receptor assembly, and a C-arm support
apparatus, wherein a C-arm slides in an arc within a single plane
through a fixed C-slider housing, and the C-arm and C-slider
housing are mounted onto a base, the improvement comprising: a
sliding pivot point means for selectively repositioning the
rotational axis, plus C-slider housing, along an arc from
approximately horizontal, when the x-ray beam is vertical, to
between approximately 60 degrees and 40 degrees below horizontal in
a vertical plane.
Description
RELATED APPLICATION
[0001] This Utility application is based upon a Provisional
Application, Ser. No. 60/739,712, filed Nov. 25, 2005 by the same
Applicant. Applicant claims the benefit of priority from that
earlier application.
FIELD OF THE INVENTION
[0002] The present invention generally relates to support and
positioning apparatus for x-ray equipment. More particularly, the
invention relates to portable x-ray units with sliding C-shaped
arms.
BACKGROUND OF THE INVENTION
[0003] Fluoroscopy is a process for obtaining continuous, real-time
images of an interior area of a patient via the application and
detection of penetrating x-rays. Put simply, x-rays are transmitted
through the patient and converted into visible spectrum light by
some sort of conversion mechanism (e.g., x-ray-to-light conversion
screen and/or x-ray image intensifier). Subsequently, the visible
light is captured by a video camera system (or similar device) and
displayed on a monitor for use by a medical professional. More
recently, a solid-state pixelized flat panel is used for this
purpose. Typically, this is done to examine some sort of ongoing
biological process in the human body, e.g., the functioning of the
lower digestive tract or heart.
[0004] Currently, most fluoroscopy is done using x-ray image
intensifiers. These are large, vacuum tube devices (i.e., akin to a
CRT or conventional television) that typically receive the x-rays
in an input end, convert the x-rays to light and then electron
beams, guide, accelerate, and amplify the electron beams via
internal electrodes, and convert the electron beams to a minified
visible image at the device's output end. An example of an x-ray
image intensifier is shown in U.S. Pat. No. 5,773,923 to Tamagawa
(see FIGS. 1 and 2 and accompanying description).
[0005] In designing x-ray support apparatuses, the x-ray device
should ideally be positionable for use anywhere around the
periphery of a patient in three dimensions (i.e., the X-, Y-,
Z-planes). More specifically, it is typically desirable to utilize
spherical angulation, where x-rays can be directed from any loci on
an imaginary sphere centered on the patient to an isocenter of the
x-ray device. (The isocenter is the point of intersection of an
axis defined by the x-ray source and receptor and the axis of
angulation, i.e., the axis of device rotation.) Other factors to
take into account include: maintaining the x-ray beam normal to the
x-ray receptor; the size of the examination room, and the room's
ability to accommodate large devices; unrestricted access to the
patient, especially around the head area; minimizing control
complexity and/or the need for computer image correction or
manipulation; and, as always, cost.
[0006] Most current x-ray device support apparatuses utilize either
a parallelogram-shaped construct or a combination of C-, U-, and/or
L-shaped arms for x-ray device positioning and (ideally) spherical
angulation. An example of the former is shown in U.S. Pat. No.
3,892,967 to Grady et al. ("Grady '967"). In Grady '967, an x-ray
source 23 and receptor 22 are positioned with respect to a patient
P by way of an angularly-adjustable, pivoting, rotating
parallelogram 3, 5, 8, 9. This achieves 360 degrees rotation
coverage about the patient P, by virtue of the parallelogram being
rotatable about shaft 2, and 55 degrees of head/foot tilt (the arms
8, 9 can be moved in and out.) Thus, the device basically moves in
an unrestricted way on the surface of a sphere about the patient,
and the x-ray image itself inherently always remains "upright"
irrespective of the compound angles used. However, to cover from
head to foot on a six foot tall patient, the "throat depth"
(clearance) of the support apparatus has to be over six feet. This
makes the support apparatus at least ten to twelve feet long, plus
the patient tabletop has to travel at least six feet, which means
it must be eight to nine feet long. Thus, the entire system is
almost twenty feet long, necessitating a twenty-eight or thirty
foot long room, which might cause architectural problems.
[0007] Because parallelogram-based devices are so bulky, various
C-arm based devices have been developed over the years. However,
large C-arms are difficult to balance (e.g., a parallelogram can be
an entirely mechanically-balanced device), since the entire mass of
the C-shaped structure is offset to one side. Accordingly, these
have primarily taken the form of a simple, light, balanced,
C-shaped arm which holds the x-ray source at one end and the
receptor at the other end. The C-shaped arm slides in a journal,
and is positionable by way of one or more pivoting arms attached to
the journal. Such devices can deliver most of the angular coverage
of a parallelogram in a smaller space, but typically have several
severe, inherent problems, such as the inability to carry heavy
equipment without dangerous power-driven operation, and if the
C-arm slides in the journal, the image will rotate due to an
interaction of the two axes. Some parts of the spherical view
become inaccessible.
[0008] With existing C-arm based devices, as the axis of the x-ray
beam approaches the horizontal, rotating the horizontal axis only
serves to rotate the image, without changing the viewing angle.
This results in zero image rotation with a vertical beam, and 100
percent rotation (only) at a horizontal beam. In between 0 degrees
and 90 degrees the x-ray beam/positioner angular relationship is
complex, and the two rotation axes interact. The result is a tilted
image as viewed on the x-ray image screen. This effect can be
compensated for by either mechanically rotating the x-ray receptor
(and also the source collimator if a square x-ray field is
utilized) according to a pre-programmed code, or by implementing an
"image de-rotation" scheme where the image, as stored
electronically, is manipulated by digital means. However, such
systems are expensive, and can ultimately degrade the image. Some
angulations critical to cardiology are no longer achievable once
the arm is slid in its sliding bearing (i.e., its outer
sleeve).
[0009] There have been numerous variations in the design and
construction of C-arm based x-ray gantries, but two main divisions
are apparent: types where the horizontal C-arm axle comes at the
patient from the left side, and types where the C-arm axle comes
over the patient's head.
[0010] For an axle or C-arm mount that is horizontal, approaching
the patient from the left side is the ideal orientation, as the
head end of the patient is then accessible for anesthesia, nursing
care, etc. The tilt range of the "sliding C", and hence the
efficacy of the equipment, in that arrangement is unfortunately
reduced as the x-ray beam approaches horizontal, as mentioned
above.
[0011] The easiest way to visualize this is to note that when the
x-ray beam is vertical ("upwards"), any rotation of the generally
horizontal main axle of the C-arm mount also predictably tilts the
x-ray beam angle a like amount. For example, a 30-degree rotation
of the main axle tilts the x-ray beam angle 30 degrees. As long as
the main axle or pivot makes close to a right angle (90 degrees)
with the x-ray beam, the overall goal is achieved.
[0012] However, once the C-arm (a.k.a. the "C") is "slid" in its
mount sleeve, the difficulty appears. To go to the extreme, if the
C is slid by 90 degrees from its vertical position, where the beam
was vertical, to a new horizontal position with the beam is also
horizontal, and then the main pivot is rotated by the same 30
degrees, there is no change in x-ray beam angle at all. The 30
degree rotation of the main axle only serves to rotate the image
receptor, which rotates the displayed image.
[0013] Two situations result with the C slid to the horizontal beam
position:
[0014] 1) no head-to-foot, or cranio-caudal, angulation is
possible; and
[0015] 2) the image rotates on the viewing screen if the axle is
turned.
[0016] For intermediate positions along the sliding C motion, a mix
of the two situations appears, and they interact in a complex way.
The essence of the situation is that for x-ray beams near lateral,
with the C on the left side of the patient, there is very little
cranio caudal angulation available and image rotation is
severe.
[0017] These problems led to the "parallelogram" support and
positioning apparatus for x-ray equipment disclosed in the Grady
'967 patent, mentioned above, issued in 1975 to John K. Grady (the
present Applicant) and David B. Rice. That "parallelogram"
apparatus has none of the above issues, but obstructs the head of
the patient and requires a long room. The image on a parallelogram
does not rotate at all for all spherical views.
[0018] A first prior solution for the C-arm construction is to move
the C-arm to the head end permanently. However, that obstructs the
head end. It also gives very limited coverage of the patient, as
the C-arm radius is limited by the floor and the center point must
be inside the patient. Consequently, the patient's head will strike
the C-arm interior diameter before the beam is in the pelvic
area.
[0019] A second prior art solution is to mount the C-arm on a third
axis pivot, which allows it to be moved from the left side to the
head end of the patient, depending on clinical requirements. There
are many existing variations along this theme, with floor and
ceiling pivots, dual third axis pivots generating on offset, etc.
All suffer from the complexities of a third pivot, coordinating
that pivot to the other two, and adding a new source of image
rotation that interacts with the other two in a complex way. With
the recent advent of software based 3-D image reconstructions, the
impact of image rotation or shifts is really severe, often becoming
a limiting factor in the data integrity.
[0020] These problems can be solved for a stationary
catheterization ("cath") lab with a different approach--see U.S.
Pat. No. 6,789,941 ("Grady '941"), issued Sep. 14, 2004 to John K.
Grady. Grady '941 describes a C-shaped arm with a pivot fixed at 90
degrees to the beam, the whole thing traveling inside an arc. Note
that there is no sliding mount or sleeve on the C-arm mount at all;
that deletion eliminates image rotation. The "axle pivot"
(equivalent) is actually moving with the C-arm, always at 90
degrees to the main beam, a critical design differentiator.
Application of These Concepts to a Portable C-Arm Unit for
Angiography
[0021] All "Portable C-arm" x-ray systems sold to date combine a
sliding C-arm type of construction with a generally horizontal axle
or an axle fixed at some compromise angle, so the problem of
interacting angular capabilities described above are the norm. This
prevents effective use of the systems for cardiac angiography,
which requires steep angulation in both directions, with a beam
close to horizontal.
[0022] Some attempts to overcome this have included permanently
offsetting the normally horizontal axle pivot, to a fixed angle
below horizontal, and moving the sliding attachment point or C-arm
"sleeve" to a position generally about 45 degrees below horizontal.
This design was in fact originally less concerned with angular
capabilities, than with providing room for the image tube and
camera to "tuck in" in line with the horizontal axis, as a lateral
beam without head-to-foot tilt is a required capability, especially
in orthopedic surgery. Having the "grabbing sleeve" right at the
horizontal axis will cause packaging problems that conflict with a
horizontal beam--the "sleeve" and image tube try to occupy the same
space. This also prevents the image intensifier and camera from
passing the sleeve, wherever the sleeve is positioned.
[0023] Applicant tried to apply the "C-arm within an arc" concept
of U.S. Pat. No. 6,789,941 to a portable (wheeled) device. However,
Applicant soon recognized that the required vertical height of the
arc (over 7 feet) and its massive size precluded packaging that
equipment, as is, on a portable or wheeled device.
[0024] Accordingly, the primary object of the present invention is
to provide a Portable C-Arm x-ray system for angio fluoroscopy that
permits head-to-foot, or cranio-caudal, angulation without
appreciable degradation or rotation of the recorded image in the
segment of possible views most desired to be used for cardiac
angiography, generally between a vertical beam and 60 degrees to
the patient's left side from vertical. That corresponds to a
horizontal pivot and to a pivot 60 degrees below horizontal, as the
pivot must be kept at 90 degrees to the beam, or close to it, to
avoid the problems described above.
[0025] It is a more specific object to provide a Portable C-Arm
system that utilizes the sliding C-arm concept, as is well known
for many other uses, but which adds to that a limited range of
motor driven, variable location of the usually horizontal axle
pivot, giving results similar to U.S. Pat. No. 6,789,941, but
keeping a sliding C-arm mount for other customary uses.
[0026] The above and other objects of this invention will become
more readily apparent upon reading the following descriptions and
viewing the accompanying drawings.
SUMMARY OF THE INVENTION
[0027] An "Angio Capable Portable X-Ray Fluoroscopy Unit with
Sliding C-Arm and Variable Pivot Point" is disclosed. This new
Portable C-Arm system keeps the well-known sliding C concept, but
improves its efficacy. The novel system overcomes the prior limited
range of Portable C-Arm systems by adding a motor driven, variable
location of the axle pivot, giving results similar to U.S. Pat. No.
6,789,941 ("Grady '941"), issued Sep. 14, 2004 to the current
Applicant, John Grady, but keeping a sliding C-arm mount.
[0028] In the preferred embodiment, Applicant's invention comprises
a standard Portable C-arm apparatus (e.g., the apparatus of Grady
'941) having a C-arm which slides through a fixed C-sleeve mount
(a.k.a. "C-slider housing") via a drive sprocket, improved as
follows: the sleeve is mounted onto a portable base through a
rotatable tilt bearing, and a rotation axis of the bearing and
fixed sleeve can be repositioned, within an arcuate slot in the
base by a motor, from approximately horizontal, when the x-ray beam
is vertical, to between approximately 60 degrees and 40 degrees
below horizontal in a vertical plane.
[0029] The repositioning provides a head-to-foot, or cranio-caudal,
angulation without appreciable degradation or rotation of the
recorded image in the segment of possible views most desired to be
used for cardiac angiography.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a side view of an "Angio Capable Portable X-Ray
Fluoroscopy Unit with Sliding C-Arm and Variable Pivot Point,"
constructed in accordance with the present invention, depicting a
Portable C-Arm device with an angled slider pivot axis set at 45
degrees below horizontal and a sliding C at a horizontal
position;
[0031] FIG. 2 is another side plan view of the Portable C-Arm
device with the slider pivot axis raised to 0 degrees (horizontal)
from its FIG. 1 orientation and the C slid or translated to a
vertical position;
[0032] FIG. 3 is a front plan view of the Portable C-Arm device at
a cranio-caudal orientation;
[0033] FIG. 4 is a perspective view of the Portable C-Arm device in
its FIG. 3 orientation;
[0034] FIG. 5 is a perspective view of the Portable C-Arm x-ray
device with the slider pivot axis set at 0 degrees (horizontal) and
the housing having been rotated, along that axis, from a vertical
position (shown in phantom) to horizontal;
[0035] FIGS. 6 is a perspective view of the Portable C-Arm x-ray
device with the slider pivot axis set at 60 degrees below
horizontal and the housing having been rotated from a cranio-caudal
orientation (shown in phantom) at 45 degrees to 0 degrees; and
[0036] FIG. 7 is a perspective view of a portable base, with a side
cover removed (as in FIGS. 1 and 2), showing portions of a
rotatable tilt bearing means and a sliding pivot point means inside
the base.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0037] Referring to FIGS. 1-7, Applicant has disclosed a preferred
embodiment of an "Angio Capable Portable X-Ray Fluoroscopy Unit
with Sliding C-Arm and Variable Pivot Point." This new Portable
C-Arm system keeps the well-known sliding C concept, but improves
its efficacy. The novel system overcomes the prior limited range of
Portable C-Arm systems by adding a motor driven, variable location
of the axle pivot, but keeping a sliding C-arm mount.
[0038] As with U.S. Pat. No. 6,789,941 ("Grady '941") issued Sep.
14, 2004 to the current Applicant, John Grady (hereby incorporated
by reference), the drawings for Applicant's present embodiment
depict a portable C-arm support apparatus 100. The portable C-arm
support includes a large radius C-arm (preferably made of carbon
fiber) 104 having slide travel rails (e.g., 106) on opposite sides
of the C. These slide rails, together with a mid-length of the
C-arm 104, can travail within an outer, shorter C-sleeve (a.k.a.
"C-slider housing") 108. The rails are driven by sprockets (not
shown) turned by an electric motor (not shown).
[0039] One end portion of the C-arm 104 and its slide rails (e.g.,
106) are placed behind an image receptor assembly 114 centerline 1
16. That way, the C-arm can pass by the image receptor assembly 114
without interfering with (i.e., hitting) the assembly.
[0040] The C-arm projection itself, at either end, or just the end
nearest the image receptor, contains balance weights at 116. These
weights offset the unbalancing moment of the C-Arm mass and source
assembly to allow manual motion of the slide axis. These
counterweights are similar to the technique found in Grady
'941.
[0041] Applicant's preferred embodiment contains the same structure
found in Grady '941, with the following exceptions. The C-arm of
Grady '941 can be moved only in a stationary arc along the X-Y
plane (i.e., in a single plane), within a C-sleeve whose location
is fixed. Applicant's current invention preferably includes: a
rotatable tilt bearing means 120 for pivoting the arc (and
C-slider) in a Z-plane around a pivot axis (a.k.a. C-slider axis)
122; and a sliding pivot point means 124 for repositioning the tilt
bearing means 120, and pivot axis 122, in the X-Y plane along an
arcuate path. The tilt bearing means 120 and the sliding pivot
point means 124 combine to create extreme compound angles related
to cardiac catheterization ("cath").
[0042] In simpler terms, Applicant's preferred embodiment can be
thought of as a portable x-ray device of the type having an x-ray
source 102, an image receptor assembly 114, and a C-arm 104 which
slides through a fixed C-slider housing 108 mounted onto a portable
base 126, the improvement comprising: the C-slider housing 108 is
mounted onto the portable base 126 through the rotatable tilt
bearing means 120 for pivoting the arc (and C-slider housing 108)
in a Z-plane around C-slider rotational axis 122; and, the C-slider
rotational axis 122, plus C-slider 108, can be repositioned along
an arcuate slot 130 (in the base 126) by the sliding pivot point
means 124 from approximately horizontal to between approximately 60
degrees and 40 degrees below horizontal in a vertical plane.
[0043] Sliding pivot point means 124 preferably includes an arcuate
pivot carriage guide track 132, aligned with slot 130 and mounted
within the base 126. Track 132 and slot 130 have similar arcuate
lengths. Those lengths are shown as 60 degrees.
[0044] Track 132 has upper and lower surfaces, plus closed ends,
that form an internal curved housing for a C-slider pivot carriage
134. Carriage 134 has guide rollers for sliding the carriage 134
within the confines of the guide track housing.
[0045] As best shown in FIG. 7, carriage 134 is attached to the
C-slider 108 by a rotatable tilt bearing 136 that rides atop a slot
(not shown) in guide track 132. A drive gearmotor 137 selectively
slides the carriage 134 and C-slider 108 by a drive chain 138. The
drive chain 138 rides over sprockets 140 and 142, and is fixed to
the underside of the carriage by a set screw 143.
[0046] As best shown in FIG. 7, tilt bearing means 124 preferably
comprises a reversible drive motor 144 removably attached to the
rotatable tilt bearing 136 by any suitable means, such as pinning.
Motor 144 preferably has a drive shaft which extends through a slot
in the bottom of the track 132 housing, up though a hole in the
carriage 134. Motor 144 preferably is mounted on a tab 146 that
runs in a lower slot of the guide track between the guide rollers.
Other mounts and attachments would also do. A user (not shown) can
utilize the motor to selectively rotate C-slider housing 108 about
the C-slider axis 122.
[0047] Applicant has realized that the need for extreme compound
angles (related to cardiac cath) actually occur only in a series of
views generally encompassed by the receptor being on the left side
of the patient, rotated about 50 to 60 degrees around the patient,
and tilted about 35-40 degrees toward the head of the patient. This
"compound angle" will best display the coronary arteries of the
heart, by having the x-ray beam impinge on them approximately
orthogonal to them as they lie in their normal anatomical position.
This view is critical to doing accurate measurements, etc., as when
placing coronary stents.
[0048] To accomplish these views, it is only necessary to keep the
pivot of the axle of the C orthogonal for only the limited range of
possible views needed for a cardiac examination. The invention is
preferably used with a patient table having a slidable top. That
enables the patient to be slid within the confines of the C-arm
(i.e., interior of C-arm "diameter") and withdrawn after using the
equipment.
[0049] The reason for Applicant's sliding mount is to allow
mounting the entire system on the cart-like base 126. This base
does not need an outer arc track higher than the horizontal beam.
Yet this is capable of mimicking the large system in its cardiac
abilities for angles between a vertical beam and a beam
approximately rotated 60 degrees to the patient's left. It does
this by moving the axle pivot from about horizontal (when the
useful x-ray beam is vertical) to about 60 degrees (or more) below
horizontal, when the main beam is rotated 60 degrees to the left
(looking from the patient's feet).
[0050] The moving axle pivot replaces the prior "sleeve" or sliding
motion in this critical area, enabling cardiac cath related angles
to be achieved on a "portable" C-arm, without using the "sliding"
motion; yet the sliding motion remains for other uses.
[0051] It should be understood by those skilled in the art that
obvious structural modifications, or usages, can be made without
departing from the spirit or scope of the invention. For example,
the portable C-arm support could be used for other fluoroscopy,
beyond angio fluoroscopy; or, a gearing system could be substituted
for the drive chain. Accordingly, reference should be made
primarily to the appended Claims rather than the foregoing
description to determine the spirit and scope of the invention.
* * * * *